(2) Through a properly programmed control, a computer could have a very
simple fixed physical structure, without the need for changes in hardware. Yet, it could
be perform any kind of computation effectively.
(3) The stored program theory was fundamental for future generations of
high-speed digital computers. This theory encompassed a number of related ideas.
(a) Binary system. Equipment design lent itself to a binary system
since electronic components are either "on" or "off," conducting or not conducting,
magnetized or not magnetized. Thus, instructions could be coded as numbers and
stored internally in the machine along with the data.
(b) Data and instructions stored together. With instruction programs
and data in the same memory unit, instructions could be modified in the same way as
(c) Alterable instructions. Instructions could be altered during a
computation to make them behave differently.
(d) Sequential program control. A type of instruction that permitted the
program sequence to be interrupted and reinitiated at any point.
(e) Subroutines. Instructions that can be used repeatedly according to
the way the computation progresses.
(f) Programs in the subroutine library. Frequently used subroutines
kept intact in "libraries" and read into memory when needed.
(g) The memory as assembly place for instructions. Parts of a long
computation were stored, worked on piecewise, and subsequently assembled.
(h) Read and write memory . A type of memory that provides almost
constant access to any piece of information so that the contents can be retrieved and
altered, at will, by the user.
c. First-Generation Stored Program Computer (1947).
(1) The first programmable stored program computer to incorporate Von
Neuman's ideas is EDVAC.
Another programmable computer with a stored program is EDSAC.
The first commercially available computer was the UNIVAC.